The present invention relates to inkjet printheads. In particular, it relates to plugs for sealing ink conduits between an ink compartment and a heater chip in an inkjet printhead. Even more particularly, the invention relates to laser welding such ink conduit plugs to an inkjet printhead body.
The art of inkjet printing is relatively well known. In general, an image is produced by emitting ink drops from an inkjet printhead at precise moments such that they impact a print medium, such as a sheet of paper, at a desired location. The printhead is supported by a movable print carriage within a device, such as an inkjet printer, and is caused to reciprocate relative to an advancing print medium and emit ink drops at such times pursuant to commands of a microprocessor or other controller. The timing of the ink drop emissions corresponds to a pattern of pixels of the image being printed. Other than printers, familiar devices incorporating inkjet technology include fax machines, all-in-ones, photo printers, and graphics plotters, to name a few.
A conventional thermal inkjet printhead includes access to a local or remote supply of color or mono ink, a heater chip, a nozzle or orifice plate attached to the heater chip, and an input/output connector, such as a tape automated bond (TAB) circuit, for electrically connecting the heater chip to the printer during use. The heater chip, in turn, typically includes a plurality of thin film resistors or heaters fabricated by deposition, masking and etching techniques on a substrate such as silicon.
To print or emit a single drop of ink, an individual heater is uniquely addressed with a small amount of current to rapidly heat a small volume of ink. This causes the ink to vaporize in a local ink chamber (between the heater and nozzle plate) and be ejected through and projected by the nozzle plate towards the print medium.
During manufacturing of the printheads, a single body of material, often plastic, becomes formed with a plurality of ink compartments that have ink conduits between the compartments and ink feed slots that, in turn, connect to the heater chip. The ink conduits are formed by moving core pins in the plastic molds that, in turn, cause openings in the body that require sealing, before use, so that ink does not leak.
In general, a plug adheres or welds to the opening of the ink conduit via ultrasonic vibration. Ultrasonic welding, however, often introduces flash particles or other into the printhead (which can clog the ink conduits and/or nozzle holes) which prematurely fails the printheads. Adhering has problems because of its impractical long cure time. U.S. Pat. No. 6,260,961, Seu et al, embodies an example of an ultrasonically welded or an adhered plug (seal member 66).
Accordingly, a need exists to reliably, consistently and quickly manufacture a printhead without causing clogging of the ink conduits and nozzles.
The above-mentioned and other problems become solved by applying the apparatus and method principles and teachings associated with the hereinafter described ink conduit plugs for inkjet printheads and methods for laser welding the plugs to the printheads.
In one embodiment, an inkjet printhead has a unitary body with an ink conduit between an ink outlet port of an ink compartment and an ink feed slot compatible with the ink slots of a heater chip. An ink conduit plug laser welds thereto to prevent ink from leaking from the ink conduit as the ink flows from the ink outlet port to the ink feed slot during use. In another embodiment, the ink conduit plug has a lid and an insertion portion. The lid has a laser transparent periphery that becomes irradiated with laser light to weld an undersurface of the lid over an opening (defined by a surface extending thereabout) of the ink conduit after the insertion portion gets inserted past the opening and the undersurface contacts the surface. Techniques for laser welding include advancing a laser beam around a topside periphery of the lid or simultaneously welding the topside periphery.
In still other embodiments, the ink conduit plug has two plug sections banded together with either a flexible material for bending the plugs sections into a specific orientation or a plurality of angularly disposed links for predisposing the plugs sections in a specific orientation. The ink conduit plug having banded plug sections may additionally become laser welded to seal ink conduits of an inkjet printhead. They may also have lids and insertion portions either of which may have laser light transparency characteristics.
An inkjet printer for housing the printhead is also disclosed.
These and other embodiments, aspects, advantages, and features of the present invention will be set forth in the description which follows, and in part will become apparent to those of ordinary skill in the art by reference to the following description of the invention and referenced drawings or by practice of the invention. The aspects, advantages, and features of the invention are realized and attained by means of the instrumentalities, procedures, and combinations particularly pointed out in the appended claims.